It is generally believed that baldness and a falling-out of hair are caused by (1) an activation of androgens in organs such as the hair roots and sebaceous glands, (2) a lowering of blood flow to the hair follicles, (3) an abnormality of the scalp due to an excessive secretion of sebum, formation of peroxides, or propagation of bacteria or the like, (4) heredodiathesis, (5) neuroses due to stress or the like, (6) side effects of diseases, and (7) aging.
Accordingly, conventional hair revitalizing tonic compositions generally contain a compound by which the above-mentioned causes are eliminated or alleviated. For example, a compound capable of inhibiting the activation of androgens or a compound capable of increasing blood flow to the hair follicles is contained in the hair tonic.
Nevertheless, the mechanisms of loss and regrowth of hair are very complicated, and thus it is impossible to satisfactorily prevent baldness and a falling-out of hair simply by inhibiting the activation of androgens or by increasing the amount of blood flow to the hair follicles.